Risk of Cervical Spine Complications in Individuals with Cervical Dystonia Treated with Botulinum Toxin Therapy.

Objective: To examine the risk of cervical spine complications in individuals with focal cervical dystonia (CD) treated with botulinum toxin (BoNT) injections. Background: CD is a movement disorder characterized by involuntary twisting and turning of the neck, often accompanied by a jerky tremor. Owing to the persistent abnormal forces exerted on the cervical spine, cervical spine pathology has been reported in approximately 30% of patients; however, data on this risk in the context of BoNT therapy are lacking. Design/Methods: In a retrospective analysis of CD patients receiving BoNT therapy, we determined the prevalence of cervical spine complications, including degenerative cervical spinal stenosis, myelopathy, radiculopathy, and atlantoaxial dislocation. Data on treatments including pain medications and interventions both surgical such as cervical laminectomy, discectomy, anterior cervical discectomy and fusion (ACDF), posterior cervical instrumentation and fusion (PCF), and non-surgical like radiofrequency ablation, and medial branch blocks were extracted. In addition, we conducted a literature review of cervical spine complications reported as associated with CD. Results: In a cohort of 320 patients receiving regular BoNT therapy and followed longitudinally for 5 or more years, we found 17 individuals (5.3%) with new onset cervical stenosis (n = 11), radiculopathy (n = 5) or myelopathy (n = 4), developing after the diagnosis of CD and initiation of BoNT therapy (58.8% developing in the first 5 years). The neck pain in these individuals was managed with opioid medications in addition to BoNT injections and oral muscle relaxants. While procedures such as medial branch blocks (n = 5), radiofrequency ablation (n = 2), and epidural steroid injections (n = 8) were employed for controlling pain, surgical interventions such as laminectomy (n = 3), discectomy (n = 4), PCF (n = 1), and ACDF (n = 3) were warranted in some individuals. Conclusion: Cervical spine complications following a diagnosis of CD may necessitate opioid therapy, nerve blocks, ablative procedures, and/or surgical interventions. In contrast to prior reports from the predominantly pre-BoNT era, which estimated complication rates of approximately 30%, our cohort, well managed with BoNT therapy, demonstrated a considerably lower risk of cervical spine complications (5.3%). These findings suggest that early initiation of BoNT therapy, by effectively controlling abnormal involuntary forces exerted on the cervical spine, may reduce the risk of secondary cervical spine complications.